Reduction of edge taper in strip rolling



Dec. 28, 1965 A. H. EL-WAZIRI Filed April 24, 1963 2 Sheets-Sheet 1 I,A: t i g 30 H a l 30 3 l W 3/ 2a 28 I l I 2.9

29 28 L9 2 Lg 34 Z Attorney Dec. 28, 1965 A. H. EL-WAZIRI 3,225,580

REDUCTION OF EDGE TAPER IN STRIP ROLLING Filed April 24, 1963 2Sheets-Sheet 2 IIVVEIVTOI? ABDEL H. [L WAZl/P/ By M QMZV Af/omey UnitedStates Patent 3,225,580 REDUCTION OF EDGE TAPER IN STRIP ROLLING AbdelH. El-Waziri, Pittsburgh, Pa., assignor to United States SteelCorporation, a corporation of New Jersey Filed Apr. 24, 1963, Ser. No.275,282 6 Claims. (Cl. 72236) This invention relates to the reduction ofmetal strip and the like by cold-rolling, and is more particularlyconcerned with the control of transverse uniformity in gauge of theproduct, especially reduction in edge taper, by means of selectivelimitation of lubricants conventionally applied to the metal beingrolled, prior to roll entry.

Variation of thickness across the strip is known to be responsible for anumber of difliculties encountered in rolling, such as locked-upstresses, buckling and waviness, edge cracking and other defects.

During rolling, the resistance of the lateral spread of the material atthe center of the strip is greater than that at the edges thereof. Thiscauses a comparatively larger amount of lateral flow of the material totake place locally at the edges of the strip. Therefore, the resultingproduct is not of uniform thickness. This condition is referred to asedge taper.

In an endeavor to eliminate edge taper and thereby obtain a product ofuniform thickness, it has been proposed that roll surfaces be ground toa shape which would compensate for this effect.

The use of specially shaped rolls present many disadvantages. Forexample, in multiple-stand mills the width of the strip progressivelyincreases as the strip passes through the stands of the mill. Therefore,the rolls of the various stands must be ground to a shape suitable tocompensate for this condition. Since the dimensions of the rolls used ateach stand differ from those of the other stands of the mill, the rollsare not interchangeable. Furthermore, the use of specially shaped rollsto correct edge taper limits the use of a particular set of rolls toonly one strip width and, therefore, requires a complete change of rollseach time a strip of different width is to be rolled. Also, for thismethod to be effective the strip must be fed with its centerlinestrictly in the plane of symmetry of the mill stand. This is arequirement that is not easily met in practice.

The present invention provides a method for correcting edge taper thatcircumvents the problems encountered in the proposed roll shapingpractice. This is accomplished by limitation of amounts ofconventionally applied cold rolling lubricants, in areas adjacent to thestrip edges, preferably by totally or partially removing the lubricantover adjustable widths along the edges of the strip and thecorresponding area on the workrolls. This increases the friction betweenthe strip and the workrolls at the area of lubricant removal and therebyconstrains the lateral flow of the material at said area. The degree andarea of lubricant removal are regulated to achieve a uniform reductionacross the width of the strip.

An understanding of the details of the method of lubricant removal maybe obtained by reference to the specialized equipment employed, asdepicted in the drawings, where:

FIGURE 1 is an elevational view of a rolling mill stand with thelubricant removal devices installed to remove lubricant from stripedges;

FIGURE 2 is a partial perspective view of the roll mill stand of FIGURE1; and

FIGURE 3 is an enlarged elevational view of the rolls and strip, withthe housings of the lubricant removal devices shown in section to permitpresentation of their internal mechanism.

3,225,580 Patented Dec. 28, I965 In the interest of clarity ofpresentation, the drawings are somewhat schematic in detail, and whileessential functions are depicted, mechanical details related to theirincorporation in the apparatus may be altered without departure from theinventive concept.

With further reference to the drawings, particularly FIGURES 1 and 2,each stand of the mill is preferably supplied with two pairs oflubricant removal devices 1, each pair being composed of an upperelement 1a and a lower element 1b, each pair of devices being mountedastride the strip 2, adjacent to each edge, and adjacent to the entryside of rolls 3, to permit selective removal of lubricant from areasadjacent to the strip edges and from the corresponding areas of therolls which will contact the strip edge areas. The rolls are mounted inpillar like supports 4, to which the lubricant removal devices areconveniently afiixed as shown in the drawings.

The construction and operation of the lubricant removal devices 1 willbecome apparent by reference to FIGURE 3.

An apparatus suitable for this purpose is shown in FIF- URE 3. Acontinuous belt 10, of absorbent material, driven by a motor 11'attached to drum 11, is moistened with any suitable detergent or solventby applicator roll 12. The moistened portion of the belt then passesover drum 11 and moves toward drum 13. As the belt passes over drum 13,it contacts the surface of the workroll 3. The positioning of drums 13and 14 causes the belt when passing therebetween to contact the surfaceof the strip for an appropriate distance along the length thereof. Sincethe belt is moistened with detergent, the lubricant is removed from theworkroll and the strip over an area equal to the contact area of saidbelt. The belt is now guided in a horizontal path by rolls 16 and 17,and the sprayer 18 applies a detergent or solvent to that portion of thebelt horizontally positioned between said rolls, to dilute the mixtureof removed lubricant and detergent or solvent. The belt then passesbetween wringer rolls 17 and 19, which have their surface covered with apliable elastic material, such as rubber, and the contaminated detergentor solvent is removed from the belt. Any excess solvent from sprayers 18and the solvent removed from the belt by wringer rolls 17 and 19 fallinto a collecting basin 20 for subsequent disposal. The belt, havingbeen thoroughly cleaned by the combined action of the sprayers and thewringer rolls, again contacts the applicator roll and is moistened withthe detergent.

As shown in FIGURE 3, the applicator roll 12 is immersed in a detergentcontained in a shallow trough 21. Pump 22 maintains the detergent in theinner cylinder 23 constantly overflowing. The overflow passes into theouter cylinder 24 and from there into the sump 25. Therefore, if the topof the inner cylinder is positioned on the same horizontal plane as thedesired level of detergent in trough 21, the amount and level ofdetergent in said trough will remain constant.

FIGURES 1 and 2 illustrate essential mounting structure. The two unitspositioned above the strip are hinged to screw spindles 26 that extendalong the length of the roll. A handle 27 is attached to the ends of thespindles, and the position of the units may be changed by merely turningthe handles in the proper direction. This enables the area of lubricantremoval to be increased or decreased according to changes in operatingconditions. It also enables the position of the units to be changed toaccommodate various widths of the strip. The maximum area of lubricantremoval is determined by width of the belt.

A member 28 extends horizontally from each unit. Holes are provided inthe ends of the top members, and threaded rods 29 are passedtherethrough. The end of each rod is attached to the bottom member. Anut 39 with a coil spring 31 therebelow is screwed onto the top of thethreaded rod. By turning the nut in the proper direction, the operatormay adjust the pressure at the contact area of the belt. The magnitudeof pressure and the relative velocity of the belt, as it contacts thestrip and the workrolls, determine the degree of lubricant removal andhence the magnitude of the coefiicient of friction between the strip andthe workrolls. The speed of the motor may be regulated to achieve thedesired relative velocity.

The lower elements In may receive additional support from horizontalbars 32. These have slots 33 which are coordinately positioned withrespect to flange 34 of element In to receive spring loaded attachingbolts 35.

The detergent or solvent chosen is appropriate to the lubricantemployed. Various trade-named detergents and solvents may be employed.As indicative of the types of detergents and solvents contemplated,sodium lauryl sulphate is an example of a detergent generally applicableand examples of solvents are butyl acetate, ethylene glycol, and carbontetrachloride.

While certain specific examples have been given of the application ofthe invention, these are to be considered as illustrative for readyapplication of the invention, rather than as limiting thereof, asmodifications therein will be apparent to those skilled in the art towhich this invention pertains.

I claim:

1. The process of reduction of metal strip and the like by cold rolling,comprising removal of normally present lubricants from selected areasadjacent to the strip edges, prior to roll entry, and from thecorresponding areas of the roll surfaces about to contact said stripareas, to reduce edge taper of the strip material upon cold rolling, andcold rolling said strip.

2. Apparatus for the reduction of metal strip and the like by coldrolling comprising means for reducing an amount of normally presentlubricants from selected areas adjacent to the strip edges, prior toroll entry, and from the corresponding areas of the roll surfaces aboutto contact said strip areas, to reduce edge taper of the strip materialupon cold rolling.

3. The apparatus of claim 2 in which said means for selective reductionin amount of lubricants includes lubricant removal means comprisingpairs of lubricant removal devices adapted to be selectively positioned,in operative contact, astride strip and the like undergoing coldrolling, and in operative contact with corresponding roll areas,

each of said pairs of devices comprising an upper and lower element,each of which comprises a continuous belt of absorbent material forcontacting strip and roll surfaces; drums for carrying said belt intocontact with the strip and roll areas; motor drive means for said belt;means for moistening said belt with detergent, solvent, and the like;and means for cleaning the belt.

4. The apparatus of claim 2 in which said means for selective reductionin amount of lubricants includes lubricant removal means comprisingpairs of lubricant removal devices adapted to be selectively positioned,in operative contact, astride strip and the like, undergoing coldrolling, and in operative contact with corresponding roll areas, each ofsaid pairs of devices comprising an upper and lower element, each ofwhich comprises a continuous belt of absorbent material for contactingstrip and roll surfaces; drums for carrying said belt into contact withthe said strip and roll areas; motor drive means tor said belt; meansfor moistening said belt with detergent, solvent, and the likecomprising an applicator roll and a constant liquid level trough forsaid roll; and. means for removal of contaminated detergent, solvent,and the like from the belt comprising means for spraying the belt withdetergent, solvent, and the like, wringer rolls, and a collecting basin.

5. The process of reduction of metal strip and the like by cold rolling,comprising selective limitation of nor mally present lubricants in areasadjacent to the strip edges, prior to roll entry, and in thecorresponding areas of the roll surfaces about to contact said stripareas, to reduce edge taper of the strip material upon cold rolling, andcold rolling said strip.

6. The process of reduction of metal strip and the like by cold rolling,comprising removal of normally present lubricants from selected areasadjacent to the strip edges, prior to roll entry, to reduce edge taperof the strip material upon cold rolling, and cold rolling said strip.

References Cited by the Examiner UNITED STATES PATENTS 1,487,375 3/1924Fuchs 15l00 2,234,153 3/1941 Herbert l.2 2,318,320 5/ 1943 McFadden-80--l.2 2,555,021 5/1951 Backus 80l.2 3,002,210 10/1961 Gawne 15102CHARLES W. LANHAM, Primary Examiner,

1. THE PROCESS OF REDUCTION OF METAL STRIP AND THE LIKE BY COLD ROLLING,COMPRISING REMOVAL OF NORMALLY PRESENT LUBRICANTS FROM SELECTED AREASADJACENT TO THE STRIP EDGES, PRIOR TO ROLL ENTRY, AND FROM THECORRESPONDING AREAS OF THE ROLL SURFACES ABOUT TO CONTACT SAID STRIPAREAS, TO REDUCE EDGE TAPER OF THE STRIP MATERIAL UPON COLD ROLLING, ANDCOLD ROLLING SAID STRIP.